[FLASH-USERS] issues with radiative cooling shocks

[Ryan Farber]

Hi Antoine,

In addition to guaranteeing stability with modifications to the timestep
limiter, you can try using a non-explicit solver. The Townsend solver is
pretty easy to implement and quite stable:
https://iopscience.iop.org/article/10.1088/0067-0049/181/2/391/meta

Best,
--------
Ryan


On Thu, Oct 22, 2020 at 11:17 AM Klaus Weide <klaus at flash.uchicago.edu>
wrote:

> On Thu, 22 Oct 2020, Tomasz Plewa wrote:
>
> > If there is no timestep limiter due to cooling, implement one following
> the approach used in Burn_computeDt (or whatever the module name is). You
> should be able to
> > stabilize calculations by limiting the source term contribution to about
> 10% of the internal energy.
> >
> Just adding to that:
>
> The presence of the 'dt_Cool' column in Antoine's output indicates that a
> timestep limiter for cooling was in effect; it may just not be aggressive
> enough. So you may want to modify the file Cool_computeDt.F90.
>
> There is a hardwired factor of 0.5 in the version that I am looking at;
> you may want to change that to a smaller value, and/or add code for
> some additional timestep-limiting criteria.
>
> Klaus
>
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